In an angle coder gasket that is already known, ferromagnetic fillers or ferrites are uniformly dispersed in an elastomer matrix which is molded on a receiving support of annular shape, for example. During the operation of being mixed with the elastomer matrix, the ferrites are mechanically oriented into their easy magnetization direction, without being able to migrate within the matrix. Mechanical orientation is obtained, for example, by subjecting the matrix to shear operations. Thereafter, the matrix is molded and is subjected to the action of a magnetic field so as to magnetize the ferrites and thus obtain a continuous alternation of north and south magnetic poles.
That technique of fabricating an angular coder gasket presents the particular drawback of running the risk of presenting large ferries or ferrite masses which, when they are ill-positioned, lead to faulty magnetic coding. Furthermore, mechanically orienting the ferrites and then performing the operation of molding the matrix does not make it possible to achieve magnetization of maximum amplitude, given the magnetization values of ferrites and the ferrite content in the matrix, since certain particles are not oriented in their easy magnetization direction. Finally, coding density is restricted to 60 pairs of poles for an annular coder gasket having a diameter of about 100 millimeters (mm), in particular for coder gaskets mounted on the crank shafts of motor vehicles. Such a coding value is relatively small given the capabilities of the electronics that process the signals from the coder.